The present invention pertains to a medical implant intended to replace a vertebra, at least in part, with a view to maintaining the normal spacing between the adjacent vertebrae.
The subject of the invention finds application for vertebral replacement in the cervical, thoracic or lumbar region.
In the prior art, various variants are known for fabricating a replacement implant also called a corporectomy implant. Patent application FR 2 730 158 for example describes a spacer implant comprising two telescoping hollow elements having complementary shapes on their mutually opposite faces which engage to allow distraction movement of the elements while preventing their compression movement.
Said spacer implant makes it possible to adjust the length of the implant in situ while ensuring relative distancing between the two elements by sliding the elements as far as their final locking position. Said implant therefore has irreversible locking preventing any possible withdrawal which is a major drawback under certain inserting conditions.
Document WO 00/23 013 describes an implant comprising two hollow longitudinal elements, male and female, slidably mounted with respect to each other. This replacement implant comprises a coupling ring intended to take up a first position of non-engagement with complementary coupling means to allow free sliding of the elements with respect to each other, and a second position when it engages with the complementary coupling means to ensure locking of the elements together. The main disadvantage of said replacement implant pertains to the difficulty in rotationally commanding the coupling ring to change over from one position to the other.